1. Field of the Invention
The present invention relates to methods for identifying a graphic symbol in an image.
2. Background of the Related Art
Since about 1963, the banking industry has used Magnetic Ink Character Recognition (MICR) to facilitate automated and accurate processing of checks. MICR characters have unique fonts and are printed with a magnetic ink or toner, usually containing iron oxide. Magnetic printing is used so that the characters can be reliably read into a system, even when they have been overprinted with other marks such as cancellation stamps. The characters are magnetized in the plane of the paper with a north pole on the right side of each MICR character. The characters are read with a MICR read head which is a device similar in nature to the playback head in an audio tape recorder. As the characters move across the read head, the characters' bulbous shapes ensure that each letter induces the read head to produce a unique waveform. These unique MICR waveforms are used to reliably identify the printed character(s). The error rate for the magnetic scanning of the numbers at the bottom of a typical check is smaller than with existing optical character recognition systems. For well printed MICR, the rate of unreadable characters is usually less than 1% while the rate of misreading characters is about 1 per 100,000 characters.
U.S. Pat. No. 3,000,000 describes an automatic reading system that was one of the first efforts to use magnetic ink on a document that would be conveyed underneath a reading head to produce an output voltage. FIG. 1 of that patent shows the numeric characters 0-9 alongside the waveform that such characters would produce in the reading head. This basic concept has carried over into the MICR technology still in use today.
MICR is now standardized by the International Organization for Standardization (ISO) under standard 1004. The primary MICR font used in the United States, Canadian, UK and India is known as E-13B. The E-13B font includes only 14 characters, including the numbers 0-9 and four control characters transit, on-us, amount, and dash.